Thermostatic fuel control system



Jan. 19, 1932.4 l `E, J, TE PAS 1,842,333

THERMOSTATIC FUEL CONTROL SYSTEM Filed AApril'21, 1928 Patented Jaa' 19, 1932V UNITED sra'rss` nmtunn .1. 'rE ras.

or Laxnwoon, omo, a'ssrcnon. 'ro THE rumor. vALvn oo PATENT OFFICE 0F CLEVELND, OHIQ, A CORPORATION 0l' OHIO i This invention relates to gas ired liquid heaters and in particular the gas burner control means used in connection therewith. It is the customary practice to control liq# uid heaters of the type referred to in this applicationby means of a thermostatic valve m contact with theliquid which is being heated. The thermostatic valve automatically controls the fuel supply to the heating burner which is used in 'connection Lwith the appliance. Appliances of this type are lin some cases'provided with a. constantly burning pilot light which is independent of the operation ofthe main burner and is posltioned adjacent thereto, for the purpose of igniting the main burner when gas is ad- 1 mitted to it by means of the thermostatic valve. y

Another arrangement which is commonly n used is that of having a bylpass around the thermostatic valve which at all times admits a small supply of gas to the main burner which in this case is in operation at all times.

.The thermostatic valve is used to increase or decrease 'the ilow of gas to the burnerin accordance with the temperature of theliquid with which it is in contact.

The first named arrangementwhich contemplates the use of an independent pilot light usually includes a blue flame gas burner ofthe atmospheric type in which' a certain amount ofair is premixed with the gas before combustion takes place. Burners 'of this type are sometimes referred to as'Bunsen burners. .v One of the diiiiculties encountered in the operation of the Bunsen type of burner is that they have a tendency to flash back and burn in the mixing tube when the gass'upply .i 'g to the burner has been cut down below a certain limit. When the burner operates in this manner it produces a dangerous amount of carbon monoxide which may lead to serious results if this poisonous gas escapes from the appliance.l One of the ways in which flashing backof the burner is prevented-is by the use of a sheet of gauze between the burner orifices and the mixing tube. 5 This arrangementV is not enm vtirely satisfactory due to the fact that the which in time clogs up the l? y of a graduating thermostat with this t air which is drawn into the mixing tube usually contains dust and other forelgn-matter 0 in the gauze and eventua y closes t e passages between the burner orifices and the gasv and air mixin tube. A

This conditlon is as hazardous as the condition which the ap lication of the gauze or screen was intende to correct, and may result in the escape of unburned gas that might cause an explosion or acase of asphyxiation.

'On account of the above characteristics of the aforementioned, type of burner, the use ype. 0f burner is objectionable and a thermostat havinga snap acting. valve is now generally used in this connection and for this urpose. By the use of a sna acting valve t e gas burner is either operating at full capacity or the gas supply is entirely shut of thereto. n

This arrangement allows the use of .a gauzeless burner and practically eliminates res or o the tendency' these-burners have to flash back and burnin their mixing tube While the above arran ement elimin s great many -of the dicu ties encouhtee in the operation of the Bunsen type gas burner at the same time itnecessitates theuse of a more complicated thermostatic valve, which materially increases the cost of the appliance with which it is used and at the same timeby reason of the increased number of operating parts is more .apt to 'get out of order -than a control which luses a simple graduating' thermostat.

The second type of control above referred to, wherein the independent pilot light is dispensed with and the main burner is in o ration at all times; considerably simplifies the control but it is objectionable in that at certain times in the operation of burners of ,this type the burner operates with a ellow flame which is apt to produce consi erable amount of soot or carbon.

Another objection to both of the above named control systems is the possibility of extinguishment'of either the pilot light or Athe reduced flame of the main burner. In

vthe happeningof such an event the thermos static valve may again turn on the supply of gas to the main burner and` as there is no means present for the ignition of the gas the full iow of unburned gas escapes from the burner. Serious accidents have occurred under such conditions 'when it has been attempted to relight the burner when the appliance was full of unburned gas. Again under these conditions gas has escaped from the appliance with serious results.

One of the objects of my invention is to provide a thermostatically controlled gas urner that automatically cutsoff the mam gas supply to the burner upon extinguishment of the pilot light or reduced main burner flame.

Another object of my invention is to provide a gas burner control which is operated by a graduating thermostat of a greatly simplified design.

Another object of my invention is to provide an improved gas burner control that eficiently operates with various kinds of gas and at various gas pressures.

Another object of my invention is to provide an automatic and safety control for appliances of the type described in which the gas flow to the main burner is controlled by a single gas valve which is responsive to the temperature of the liquid which is being heated and which is independently responsive in its operation lto the pilot burner.

Another object of my invention is to provide a generally improved fuel control which contains a'minimum number of parts and a minimum number of adjustments and which is not apt to require adjustments over long periods of operation.

Another object of this invention is to provide a control and burner assembly which forms a single operatively connected unit.

A further object of this invention is to provide a cooperatively associated burner and thermostatic control in which the flow of gas to the burner is controlled by a single valve head which has independentv opening means and independent closing means which operate to safely control the flow of gasto the burner.

Another object of this invention is toprovide in a control device of the type described, a graduating auxiliary gas valve which effects the opening movement of a snap acting main supply valve.'

Another object of this invention is to provide a thermostatic valve with automatic takeup mechanism to automatically maintain the valve in proper adjustment.

.Another object of my invention is to provlde an improved valve operating` snap action mechanism which normally maintains the valve in a closed position.

Another object of my invention is to provide an improved fuel control means which utilizes the thermal energy of a small gas llame to effect the opening and closing movements of the main supply valve.

'tion to which the present application relates.

In the drawings illustrating a form of my improved control Fig. 1 is a side elevational view partly in section of my improved control adapted for use on an internal fired storage automatic water heater. lFig. 2 is a plan view of the automatic adjustment of the snap action mechanism of my improved thermostatic valve.

The illustration Fig. 1 shows in part an .internal ired storage automatic heater of the conventional type. Certain elements of the heater are not shown as they do not form a part and are not necessary for illustrating this invention'.

The reference numeral 1 refers to la storage tank having a cylindrical central flue 2 which is adapted to carry oi the heated products of combustion from the gas burner 3 and in this manner heat the liquid contents of the storage tank. The storage space of this tank is defined by the inner cylinder 2 and the outer cylinder 1 which are provided with suitable closure heads the lower head 4 being shown. The closure heads are apertured to permit the passage of the heated gases through the Hue 2. The tank 1 is surrounded with a suitable insulating material 5 which is secured in place by the outer jacket 6 and is supported by the wall 78 of the combustion chamber containing the burner 3.

The tank 1 is provided with a tapped opening 7 for reception of the thermostat supporting tube 8 which is threaded at one end for reception in tapping 7. The outer end of the tube 8 is threaded for reception in the coupling member 9. The member 9 is threaded for reception of the open end of the thermostat expansion tube 10. The inner end of the thermostat expansion tube which projects into the tank 1 is provided with closure plug 11 that forms an abutment for the thermostat rod 12. The thermostat rod 12 as is the usual practice is made of'a materi-al having a materially smaller coelicient 'escape of gastherefrom. The

:masas ing member 17 is carriedein a central opening 18, formed in the adjustment screw 19.

Theadjustment screw 19 is'provided to ad ably received inthe T tting 12 and is provided with'a closure cap 21 to revent the "fitting 12 receives at one end the couplin member 9 and is provided with'aninternafly threaded opening 22 for the assembly of "the operating elements of the thermostat. ing 22 Vis adaptedto be closed by `a suitable plug if so desired.v f

The supporting tube 8 of the thermostat has an internal dlameterV which is somewhat larger than the outer diameter of the thermostat ex ansion tube 10 allowing free space Yso between t ese elements which ermits liquid from thetank 1 to contact with `Athe entire length of the tube 10. ,This construction increases the sensitivity of the thermostat by exposing a relatively great length of expansion tube to the liquid by whose temperature itis adapted to becentrolled.

The Afulcrum lever 15 is housed in a tube 23 which is threadably received in the lower opening of the `T: fittingY 12. The lower end ofthe tube 23 is provided with a union connection 24 providin a detachable connection with the lower fitting 25. i The side opening 26 of the T fittin A25 lis internally threaded for reception of t e guide, block 27. A second opening 28 inaxial alignment with y the block 27 is provided withl an adjustable cap 29 which provides an abutment for the compression spring 30.

`The lowerend of the fulcrum lever 15 vis forked and has an arcuate cut-out ortion 31 for reception .of the pin 32. [The pm 32 is `carried on the outer end of 4the plunger 33.'l

The spring is compressed between the outer end of the plunger 33 andits adjustmentcap 39 and serves vto'maintainthe bear-` ing pin 32 of the'plunger in :contact with the A fulcru'm lever15 at the bearing point 31. In

constrained this manner the fulcrum` lever 15 is held in contact with the thermostat rod 12 and is to follow the movement of this4 rod. f

The spring 30 byholding the plunger 33 lin contact with the lower end of the fulcrum lever 15 -causes the plunger' to follow the' movements of the 'lower end of the .fulcrum lever..y 3 The innerend of the plunger 33 has' an extending portion 34 vwhi iso'fjsmaller .diameter than the rest of the plungerand under certain conditions is adapted to contact with the valve head 35. The plunger 33 is accurately fitted in the central bore of the coupling member 27. s

Thecoupling member 27 is providedA with an opening 35A which is incommunication with the conduit 36 by means of suitable pipe lThe open-v fittings 37 The lunger 33 cooperates with theopening 35 orming a cylindrical slide valve which is adapted to cover and uncover s the opening 35 and permit the fiow `of gas fromthe valve body 38 to the conduit 36 and thence to the auxiliary burner 37.

carried in the block 39 and is adapted to be connected by the conduit 7 5 to the fuel supply lline 40 at some point ahead of thethermostatic valve. The'burner 38 is adapted to .the t'hermostatic` main burner supply valve, s

which opens and closes in accordance with the movements of the thermostat which is under control of the the heater. ,Y

The lower opening 42 of the T fitting 25' is internally threaded for reception of a suitable closure plug. The valvebody 38 is threaded at its inlet end for reception of the gas supply conduit 40 andisthreaded at its outlet end for connection to a conventional angle valve 43 having an adjusting needle 44 to control maximum flow of gas to theconduit 45, which is in communication with the burner 3. i

The valve body 38 is provided with a valve seat 46 which cooperates with the valve head 35 in thecontrol of gaseous fuel to the burner 3., An extending shoulder or flange 47 is formedon the valve body for the reception and mounting of the valve frame 48 which is held -in lace by means of the cap screw A second burner or ignition pilot 38 is liquid temperature of The upper end of theqlever 55` is pivotally mounted at 56 in a suitable extension 57 formed on the valve frame 48. A conical depression or bearing is formed in the extension 58 of the lever 55. 'A spring'abutment 59..l1avi ng a conical extension is supported in the bearing or'depression formed in the boss 58 ofthe lever 55. A similarly formed spring abutment 60 is carried in like manner in a conical depression formed vin the head ofthe bolt 50. A compression spring 61 is positioned between the spring abutments 59 and 60 and serveslto vurge the lever 55 to its extreme left hand position as viewed in Fig. 1.

The forked end 54 ofthe lever 55 is provided with contacting edges 62, adapted to engage the side walls formed on the valve stem 52 by the slots 53 andin this man-ner cause the valve stem and its associated valve head to follow the movements of the lever 55. One end of the toggle link 63 is pivotally mounted at 64 in the lever 55. A pair of adjusting screws 65 are adjustably received in the laterally extending portion 66 which forms a part of the toggle link 63. The adjustingy screws 65 are provided for the purpose of limiting the arc of swing of the toggle link 63 about its bearing 64.

The other end of the toggle link 63 is pivotally connected at 67 to the adjustable toggle link 68. The toggle link 68 is provided with a rectangular opening for reception of the ratchet member 69. Ratchet member 69 is secured by means of a ball and socket joint 70 to the :tree end of a strip of bimetallic thermostatic metal 71. The ratchet member 69 is provided with a series of notches 72 which cooperates with the flat spring 73 which is secured to the link 68 by means of a screw or rivet 74. By this arrangement any permanent distortion or change in the shape of the thermostatic strip 71' is automatically taken care of and compensated for.

It will be noted that this automatic adjustment works in one direction and will take up any distortion in the strip 71 which would cause it to swing to the left as viewed inv Fig. 1. All of the strains to which the thermov static member 71 is subjected are in a direction which would tend to cause it to be bent in the direction suggested and in order to keep the valve parts in proper adjustment it is only necessary to provide a take-up for movement of the thermostat metal in the indicated direction.

With the operating elements of the thermostatic valve in the position shown in Fig. 1, which is the closed position of the valve, upon movement of the thermostatic strip 71 to the right, induced by heat from the burner 37 the toggle links 63 and 68 are moved to the right. This motion is transmitted to the oscillating lever swinging it to the right and causing the compression of the spring 61. When the thermostatic strip 71 has moved the above named elements a certain distance, de-

- termined by the relative adjustment the bear- 'ing points 70, 67 and 64, the toggle links 68 and 63 will both lie in the same plane.

`Further movement of strip 71 causes the bearing point 67 to drop below the plane of the bearing points 70 and 64. The instant this. event takes place the bearing point 67 snaps to its lowermost position as determined by the adjusting screws 65. In this action the upper adjusting vscrew moves out of contact with the lever 55 and the lower adjusting screw 65 is brought into contact therewith. The effect of this movement of the toggle links is to shift the eiective lever arm which the links make between the lever 55 and the strip 71.

By this lengthening of the lever arm or vthev would occupy when shifting ofthe pointv of application of the force transmitted by the greatly stressed thermostatic element 71, the lower end of the oscillating lever 54y is moved to its extreme right hand osition carrying with it the valve stem 5 and its associated valve head 35. This action uncovers the valve seat 46 admitting a supply of gas by way of the conduit 45 to the burner 3. It will be noted that the contacting edges 62 of the lever 55 have a certain amount of free movement before, they engage the valve stem 52. Thismovement is suflicient to allow the snap action mechanism to pass its dead center position, whereupon it completes its full movement with a snap motion.

In a similar manner when the free end of the thermostatic strip 71 moves to the left of the position it occupies when the valve is opened, the toggle links 63 and 68 will pass their neutral or in-line position and snap upwardly by reason of the force of the sprlng g 61 and in this manner the valve is closed with a snap motion. In the closing operation of the valve, which is effected by the spring 61, the lever arm with which the spring is working against the strip 71 is lengthened when the links 63 and 68 snap to their upper position and the spring 61 then has enough force available to close the valve.` The adjusting screws 65 provide an adjusting means to limit the swing of the link 63 about its bearing point 64. The manner in which the complete control operates is as follows.

Let it be assumed that the parts are in the position shown in Fig. 1 which is the position the water in the tank which had been previously heated has cooled sulliciently to cause This takes place by reason of the different coellicients of thermal expansion of these elements and causes the end of the rod in contact with the bearing 14 to move to the right. This movement is transmitted by the lever 15 to the plunger 33, which is shifted to its extreme right hand position as shown in Fig. 1. It is assumed that the conduit 40 is in communication with a source of gas supplv and in this manner a supply of gas is a mitted to the .port 35 and conducted by way of the conduit'36 to the burner 37.

If the pilot light 38 is burning, gas emitted from the burner 37 is ignited thereby and serves to heat thermostatic strip 71 which is in alignment with and adjacent to the llame of the burner 37 Upon heating of the thermostatic strip 71 its upper free end tends to move to the right. This strip is of the type of thermostatic metal having one side formed of a metal having a high coefficient of thermal expansion and the other side being formed of the dilferential contraction' of the tube 10 and the rod 12.

to form a unitary piece vof metal which changes its` shape with changes in temperature. t

In the present instance the thermostatic 5- strip 71, which is held in place against the valve frame 48 by means of the pilot block 39,

upon being heated tends to assume the shape o the are of acircle. Its upper end is in this manner shifted to the right moving the lo toggle links 63 and 68 and 1the oscillating lever 55 and associatedvalve stem 52 and valve head 35 in the manner previously described and opening the a supply of gas to the burner 3. At the in- 15 stant the valve opens it shifts to its extreme right hand position covering the valve seat 76 which is formed in the member 27. In this manner the supply of gas is temporarily shut oif to the burner 37.

In a short time the thermostatic strip 71 cools and shifts tothe left allowing the valve head under the iniiuence of the spring 77 and associated valve operating parts controlled by spring 6l to follow this movement. This movement of the valve head 35 by the spring 77 causes the valve seat 7 6 to be uncovered and again placing the' conduit 36 in communication with a source of gaseous fuel supply. In this manner gas is re-admitted to burner 37 which in turn is again ignited by the flame of the pilot burner 38 and reheating of the thermostatic strip 71 then takes place.

In the actual operation of the device it has been observed that upon opening of the valve the auxiliary burner 37 is completely extinguished and upon the re-admission of gas thereto this pilot burns with a very small flame which is just suflicient to maintain the valve in open position. When too much gas is admitted to the burner 37 the strip 71 shifts further to the right and cuts down the supply of gas to the burner 37. By this arrangement the thermostatic strip 71 regulates and measures out a proper amount of gas to maintain the valve in open position.

en water in the tank 1 has reached .a predetermined temperature the thermostatlc rodand tube 10 and 12 respectively have shifted to the left. This shifting of the rod and tube 10 and 12 allows the spring 30 to shift the lowerV end of the fulcrum lever and the associated plunger 33 to the left, covering the port 35 and cutting oil'` the supply of gas to the burner 37. When this event t es 55 place, namely extingulshment of the burner 37 the thermostatic strip 71 cools and allows the com ression spring 61 to snap the valve to its c osed position in the manner previously described.

50 If for. any reason the valve operating parts fail to function as intended and the burner 3 is not extinguished at the proper time continued heating of the water will cause the plunger 33 to be shifted still further to the 86 left and upon continued movement of this valve and admitting element the reduced extension 34 will contact with the valve head 35 and positively move it to its closed position. This action would take place only under abnormal conditions as previously outlined.

By this arrangement of a liquid temperature responsive thermostatic valve and a flame responsive thermostatic valve a novel control is provided for heaters of the type described, that positively and safely controls the How of gaseous fuel in such appliances.

If for' any reason the pilot burner 38 should become extinguished there will normally be no means provided to ignite gas emitted from the burner 37 and consequently 1t will be impossible to turn on the main gas supply to the main burner 3, thus preventing the escape of a dangerous amount of gas therefrom.

The independent closure of the valve which is effected by means of the tank thermostat causing the element 34 to engage the valve head 35 when the liquid within the tank exceeds a predetermined temperature provides an independent safety feature which further insures the safe operation of this control.

Another important feature of this control is due to the fact that the thermostatic valve 4l, is normally in a closed position. Should breakage of the thermostatie strip 71 occur or failure of the toggle links 63 or 68, the

. spring 6l would operate to maintain the valve 1n closed position. In the event of breakage of the spring 6l the spring 77 would serve the same purpose and under almost any conceivable condition the valve would tend to fall in a safe or closed position.

Furthermore, it is to be understood that the particular forms of apparatus shown and described, and the particular procedure set forth, are presented for purposes of explanation and illustration and that various modifications of said apparatus and procedure can be made without departing from my invention as defined in the appended claims.

I claim:

1. A snap action mechanism comprising, a pivotally supported oscillating lever, resilient means engaging one side of said lever, a toggle link pivoted to said oscillating lever and substantially perpendicular Y thereto, means to adjust the arc of movement of said link about said lever, a second toggle link pivotally connected to said first named toggle link and actuatingmeans connected to said second toggle link.

2. A snap action mechanism comprising, a vertically disposed pivotally supported oscillating lever, spring resisted means in operative engagement therewith, actuating means and a pair of horizontally disposed toggle `links pivotally connected to each other interposed between said actuatingmeans and said oscillating lever and operatively connected therewith and adjusting means provided by one of said toggle links to vary the length thereof.

3. A snap action mechanism comprising, a pivotally supported oscillating lever, spring resisted means in operative engagement therewith, actuating means and a pair of pivotal- 1y connected toggle links interposed between said actuating means and said oscillating lever and operatively connected therewith and adjustment take-up means provided by one of said toggle links comprising, a ratchet having teeth formed thereon and means to engage said teeth to vary the length of the said toggle link.

4. A snap action mechanism comprising, an oscillating lever pivotally supported at one of its ends, a pair of pivotally joined toggle links one of which is connected to said oscillating lever substantially perpendicular thereto, operating means connected to the other of said toggle links, means to automatically adjust the length of one of said links, and means to vary the arc of travel of the other of said toggle links about its connection to said oscillating lever.

5. In a valve, a snap action mechanism comprising, an oscillating lever pivotally supported at one of its ends, a pair of pivotally joined toggle links one of which is connected to said oscillating lever substantially perpendicular thereto, resilient means associated with said oscillating lever, operating means connected to the other of said toggle links, and valve means comprising, a valve stem, and valve head operativelyT associated with said oscillating lever.

6. In a valve, a valve body having a valve port formed therein, an oscillating lever pivotally supported at one of its ends, a pair of pivotally joined toggle links one of which 1s pivotally connected to said oscillating lever substantially perpendicular thereto, resilient means associated with said oscillating lever, operating means pivotally connected to the other of said toggle links, a valve head, a valve stem connected thereto and operatively associated with said oscillating lever, and a compression spring in contact with said valve lead to assist in moving it to its closed posiion.

7. A liquid heater comprising, a storage container, a gas burner adapted to heat the liquid contents of said container, thermostatic elements responsive to the temperature of the liquid in said container, a fulcrum lever associated therewith and valve means controlled by said fulcrum lever, an auxiliary gas burner under control of said valve means, and a thermostatic valve having an opening in which said valve means are supported, said thermostatic valve being adapted to be moved to open position when a llame is slipported by said auxiliary burner.

8. A liquid heater comprising, a storage vessel, a gas burner to heat contents of said storage vessel, a thermostatic valve to controllthe iiow of gas to said burner, an auxiliary burner to supply the energy required for the operation of said thermostatic valve, a compounding lever, thermostatic elements operatively associated with said compounding lever, a sleeve valve comprising a port and a plunger under control of said lever said plunger being adapted to control the liow of gas through said port and to contact with said thermostatic valve to move it to closed position.

9. A safety control for gas burning appliances comprising, a main heating gas burner, thermostatic means responsive to the temperature of the medium which is being heated, an ignition pilot burner adjacent said main heating burner, an auxiliary burner adjacent said ignition burner, a thermostatic element adjacent said auxiliary burner and adapted to be heated thereby, snap action means connected to said thermostatic element, and valve means controlled by said snap action mechanism and adapted to be controlled by said irst named thermostatic means independently of the operation of said auxiliary burner.

10. A safety control for gas burning appliances comprising, a main heating gas burner, thermostatic means responsive to the temperature of the medium which is being heated, an ignition pilot burner adjacent said main heating burner, an auxiliary burner adjacent said ignition burner, a thermostatic element adjacent said auxiliary burner and adapted to be heated thereby, snap action means connected to said thermostatic element, and valve means controlled by said snap action mechanism adapted to be controlled by said first named thermostatic means independ- .ently of the operation of said auxiliary burner, said first named thermostatic means being adapted to control the How of gas to said auxiliary burner.

11. A safety control for gas burning appliances comprising, a main heating gas burner, an ignition pilot burner adjacent said main heating burner, an auxiliary burner adjacent said ignition burner, a thermostatic element adjacent said auxiliary burner and adapted to be heated thereby, snap action means connected to said thermostatic element, valve means controlled by said snap action means, and thermostatic means responsive to the temperature of the liquid being heated and adapted to control the iiow of gas to said auxiliary burner and to positively shift said valve means to closed position.

12. A snap action mechanism comprising an oscillating fulcrum lever pivotally supported at one of its ends, a pair of toggle links connected to said fulcrum lever and forming substantially a right angle therewith, resilientmeans associated with said lever to oppose its movement in one direction and operating means connected to said toggle links, said toggle links being adapted to shift and change the point of application of the force of said operating means on said lfulcrum lever upon a predetermined movement of said lever about its bearing. Y

13. A snap action mechanism comprising a, spring resisted oscillating lever, operating means for said lever, and a pair of pivotally joined toggle links connecting said operating means to said oscillating lever forming substantially a right angle therewith and being adapted to vary the point of application of the force of said oscillating means on said oscillating lever upon a predetermined movement of said oscillating lever.

14. A snap action mechanism comprising a fulcrum lever, actuating means therefor, re-

silient means to continuously oppose the movement of said lever in one direction, and means connecting said actuating means with said lever and bodily movable therewith adapted to vary the mechanical advantage of said lever by quickly shifting the point of application of the force of said actuating means on said lever upon passing through a position of unstableY equilibrium and thereby completing the stroke of said lever with a snap movement.

15. A liquid heater comprising, a storage vessel, a main gas burner to heat contents of said storage vessel, a pilot burner therefor, a thermostatic valve to control the flow of gas to said main burner, an auxiliary burner positioned adjacent said pilot burner and said valve to supply the energy required for the operation of said valve, a device controlled by a condition of the liquid in said vessel, and supplemental valve means actu ated by said device to control the iow of gas to said auxiliary burner and to engage and vmove said thermostatic valve to its closed position.

16. A liquid heater comprising, a storage vessel, a, main gas burner to heat contents of said storage vessel, a pilot burner therefor, a thermostatic valve to control the flow of gas to said main burner, an auxiliary burner positioned adjacent said pilot burner and said valve to supply the energy required for the operation of said valve, a devlce controlled by a condition of the liquid in said vessel, and supplemental valve means actuated by said device to control the flow of gas to said auxiliary burner and thereby cause the functioning of said main burner under normal operating conditions and under abnormal o erating conditions said device is arrange to `cause said valve means to engage and move said thermostatic valve to its closed position.

17. A water heating device comprising, a storage vessel, and a main gas burner for supplying heat thereto in combination with a thermostatic valve located adjacent said having a bywhereof I ailix my signature. EDWARD J. TE PAS.

to said auxiliary gas burner. 

